Unit 3 - Chronic Inflammation & Hypersensitivity Flashcards
Why is a persistence of antigens important in chronic inflammation?
antigens constantly call in more macrophages
When do you get an abscess?
acute inflammation fails to eliminate the stimulus
What causes the liquefaction seen with abscesses?
due to neutrophil enzymes
What is the role of fibroblasts in the formation of an abscess?
produce collagen and form a thin CT around the exudate
What is the name of the enzyme that liquefacts neutrophils?
myeloperoxidase
What is inside the pyogenic membrane?
vessels to allow continual recruitment of neutrophils
the inner wall of an abscess that is made up of granulation tissue:
pyogenic membrane
A track made by the body to drain pus:
fistulas
Why don’t bird liquefy purulent material?
don’t have the enzymes to support it
Granulomatous means:
MACROPHAGES
What is the gross appearance of granulomatous inflammation?
Diffuse: tissue appears thickened
Nodules: firm, various sizes
Microscopically, granulomatous inflammation should have:
- LOTS of macrophages
- accompanied by lymphocytes, CT, plasma cells
More secretory and less phagocytic than typical macrophages:
epithelioid macrophages
Large, multinucleated cells that arise from the fusion of macrophages:
giant cells
Which cell looks like a fried egg?
plasma cell
When macrophages are in aggregates, they are referred to as:
granulomas
What is the characteristic look of classic granulomas?
- central core of caseous necrosis
- zone of epithelioid macrophages and giant cells
- zone of lymphocytes
- outer zone of fibroblasts and fibrosis
Th2 –>
diffuse granulomatous inflammation
Th1 –>
nodular granulomas
Johne’s is caused by:
Mycobacterium paratuberculosis
John’s is characterized by:
no well defined nodules
Grossly, lymphocytic inflammation is:
difficult to determine
Microscopically, lymphocytic inflammation should have:
lymphocytes (that can be mixed with plasma cells)
If extensive infiltrates are present in lymphocytic inflammation, it may affect the tissue by:
giving it a white/tan color
When do lymphocytes enter unresolved areas of acute inflammation?
24-48 hours
Plasma cells secrete:
antibody
Dense infiltrate of eosinophils with macrophages, varying numbers of lymphocytes, and plasma cells:
eosinophilic granulomas
Eosinophils are recruited into and stimulated to proliferate by:
IL-5, eotaxin
Green coloration to a mass often indicates:
eosinophils
Contribute to the structural integrity of tissue:
fibroblasts
synthesis of collagen and extracellular matrix proteins:
fibroblasts
What do fibroblastic growth factors signal?
proliferation (can lead to extensive fibrosis)
Dense accumulation of fibroblasts and collagen =
fibrous CT
What are the four phases of wound healing?
- hemostasis
- inflammation
- proliferation
- remodeling
Can lead to a hypertrophic scar (aka proud flesh):
excessive granulation
Seen when fibroblasts and endothelial cells have proliferated to fill in tissue defects:
granulation tissue
Often will look granular on gross surface, but often bleeds:
granulation tissue
Seen when edges of the wound are directly apposed. Heals rapidly with little trace of wound:
1st intention healing
Seen when the wound is gaping or infected. Has disorganized CT:
2nd intention healing
Epithelial cells at the periphery proliferate:
epithelialization
For epithelialization to properly occur, what must the epithelial cells move along?
the BM
List the three most common types of diseases where the response to foreign or self antigens is abnormal or inappropriate:
- hypersensitivity reactions
- autoimmunity
- immunodeficiency
immediate hypersensitivity
type 1
cytotoxic hypersensitivty
type 2
immune complex hypersensitivity
type 3
delayed hypersensitivity
type 4
an inappropriate or exaggerated response to certain antigens:
hypersensitivty
develops rapidly (within minutes) following exposure to an antigen binding to IgE:
type 1 hypersensitivity
In antigen processing, if IL-4 predominates then Th2 lymphocytes will:
induce B cells to produce IgE
What other substances (aside from IgE) can activate mast cells?
- cytokines
- complement
- drugs
- physical stimuli
When mast cells are activated by something other than IgE, it is called an:
anaphylactoid reaction
What are some of the generalized systemic effects of type 1 hypersensitivity?
- drop in bp
- bronchoconstriction
- laryngeal edema
- pulmonary congestion
When type 1 hypersensitivities are localized:
the clinical signs and pathology are restricted to a specific tissue (commonly epithelial surfaces)
What are some of the routes of exposure for allergic dermatitis (type 1)?
- inhalation
- ingestion
- percutaneous absorption
A genetic predisposition of allergic dermatitis is referred to as:
atopic dermatitis
Red raised areas associated with allergic dermatitis are most often:
around the muzzle, periocular area, conjunctiva, and interdigital areas
swelling of the skin and mucous membranes:
angioedema
cell destruction mediated by the presence of antibodies directed against cell surface antigens:
type 2 hypersensitivity
What are the three mechanisms of type 2 hypersensitivty?
- complement mediated
- leukocyte mediated
- antibody against cell surface receptor
What are the clinical signs of transfusion reactions (type 2)?
acute hemolytic anemia
What are gross/histo lesions associated with transfusion reactions?
splenomegaly and hemosiderosis of various tissues
What is the pathogenesis of neonatal isoerythrolysis?
- mother develops antibodies against fetal erythrocytes
- leakage of fetal erythrocytes across the placenta
- antibodies to fetal erythrocytes are concentrated in the colostrum
- absorption of colostrum results in acute hemolytic crisis in the newborn
What are some of the clinical signs associated with thrombocytopenia (type 2)?
petechiae and purpuric hemorrhage
Antigen antibody complexes which form in the circulation or in tissues that become “stuck” or lodged in tissue:
type 3 hypersensitivity
Size of the immune complex associated with type 3 hypersensitivity determines:
pathogenicity
What systems cause damage to the vessels in type 3 hypersensitivities?
complement and neutrophils
What type 3 hypersensitivities are localized:
an area of tissue necrosis forms from acute necrotizing vasculitis (arthus reaction)
The amount of tissue damage seen with type 3 hypersensitivity is dependent on:
quantity of complexes formed
Systemic type 3 hypersensitivities are the result of:
persistent infections, autoimmune diseases, or inhalation of foreign antigens
a delayed hypersensitivity mediated by specific T-lymphocytes following exposure to antigen
type 4
Which type of hypersensitivity is chronic and antibody independent?
type 4
In delayed hypersensitivity, what stimulates the infiltration of lymphocytes and macrophages to the site?
persistent antigen
persistent antigen that results in granulomatous and lymphocytic inflammation:
granulomatous hypersensitivity (type 4)
What is the most important thing to keep in mind about hypersensitivities?
- categories can overlap
- strict categorization of hypersensitivity reactions is an oversimplification
What are the mechanisms of autioimmunity (3)?
- release of sequestered antigens
- alteration of self antigens
- alteration of immune reactivity
Many autoimmune diseases are:
type 2 or 3
Which gender has a higher prevalence of autoimmunity?
females
What are some of the genetic susceptibilities of autoimmunity?
species and breed predilections
